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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Qt' OpenGL widgets as an ActiveX (executable)</h1>

 

The ActiveX control in this example uses the QGlWidget class in
Qt to render an OpenGL scene in an ActiveX. The control exposes a few
methods to change the scene. The example is based on the 
<a href="opengl-box-example.html">"box" example</a> from the standard 
Qt distribution.
<p> The example demonstrates the use of the default factory and 
<a href="qaxfactory.html#isServer">QAxFactory::isServer</a>(), and the implementation of an additional COM 
interface using <a href="qaxbindable.html">QAxBindable</a> and <a href="qaxaggregated.html">QAxAggregated</a>. The server executable 
can run both as an ActiveX server and as a stand alone application.
<p> 

The application uses the default factory as provided by the 
<a href="qaxfactory.html#QAXFACTORY_DEFAULT">QAXFACTORY_DEFAULT</a> macro to expose the <tt>GLBox</tt> widget as an ActiveX 
control.
<pre>    #include &lt;<a href="qaxfactory-h.html">qaxfactory.h</a>&gt;

    QAXFACTORY_DEFAULT( GLBox,
                        "{5fd9c22e-ed45-43fa-ba13-1530bb6b03e0}",
                        "{33b051af-bb25-47cf-a390-5cfd2987d26a}",
                        "{8c996c29-eafa-46ac-a6f9-901951e765b5}",
                        "{2c3c183a-eeda-41a4-896e-3d9c12c3577d}",
                        "{83e16271-6480-45d5-aaf1-3f40b7661ae4}"
                      )
</pre>The implementation of <tt>main</tt> initializes the <a href="qapplication.html">QApplication</a> object,
and uses <a href="qaxfactory.html#isServer">QAxFactory::isServer</a>() to determine whether or not it is
appropriate to create and show the application interface.
<pre>    /*
      The main program is here.
    */

    int main( int argc, char **argv )
    {
    <a name="x2732"></a>    QApplication::<a href="qapplication.html#setColorSpec">setColorSpec</a>( QApplication::CustomColor );
        <a href="qapplication.html">QApplication</a> a(argc,argv);

        if ( !QGLFormat::hasOpenGL() ) {
            <a href="qapplication.html#qWarning">qWarning</a>( "This system has no OpenGL support. Exiting." );
            return -1;
        }

        if ( !QAxFactory::isServer() ) {
            GLObjectWindow w;
            w.<a href="qwidget.html#resize">resize</a>( 400, 350 );
    <a name="x2733"></a>        a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &amp;w );
            w.<a href="qwidget.html#show">show</a>();
            return a.<a href="qapplication.html#exec">exec</a>();
        }
    <a name="x2731"></a>    return a.<a href="qapplication.html#exec">exec</a>();
    }
</pre>
<p> 

The <tt>GLBox</tt> class inherits from both the <a href="qglwidget.html">QGLWidget</a> class to be able
to render OpenGL, and from <a href="qaxbindable.html">QAxBindable</a>.
<pre>    #include &lt;<a href="qaxbindable-h.html">qaxbindable.h</a>&gt;

    class GLBox : public <a href="qglwidget.html">QGLWidget</a>,
                  public QAxBindable
    {
        <a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a>
</pre>The class reimplements the <a href="qaxbindable.html#createAggregate">QAxBindable::createAggregate</a>() function from <a href="qaxbindable.html">QAxBindable</a>
to return the pointer to a <a href="qaxaggregated.html">QAxAggregated</a> object.
<pre>    public:

        GLBox( <a href="qwidget.html">QWidget</a>* parent, const char* name );
        ~GLBox();

        <a href="qaxaggregated.html">QAxAggregated</a> *createAggregate();

    public slots:

        void                setXRotation( int degrees );
</pre>The rest of the class declaration and the implementation of the OpenGL
rendering is identical to the original "box" example.
<p> 

The implementation file of the <tt>GLBox</tt> class includes the <tt>objsafe.h</tt>
system header, in which the <tt>IObjectSafety</tt> COM interface is defined.
<pre>    #include &lt;objsafe.h&gt;
</pre>A class <tt>ObjectSafetyImpl</tt> is declared using multiple inheritance
to subclass the <a href="qaxaggregated.html">QAxAggregated</a> class, and to implement the IObjectSafety
interface.
<pre>    class ObjectSafetyImpl : public <a href="qaxaggregated.html">QAxAggregated</a>,
                             public IObjectSafety
    {
    public:
</pre>The class declares a default constructor, and implements the queryInterface
function to support the IObjectSafety interface.
<pre>        ObjectSafetyImpl() {}

        long queryInterface( const <a href="quuid.html">QUuid</a> &amp;iid, void **iface )
        {
            *iface = 0;
            if ( iid == IID_IObjectSafety )
                *iface = (IObjectSafety*)this;
            else
                return E_NOINTERFACE;

            AddRef();
            return S_OK;
        }
</pre>Since every COM interface inherits <tt>IUnknown</tt> the <tt>QAXAGG_IUNKNOWN</tt> macro
is used to provide the default implementation of the <tt>IUnknown</tt> interface.
The macro is defined to delegate all calls to <tt>QueryInterface</tt>, <tt>AddRef</tt>
and <tt>Release</tt> to the interface returned by the controllingUnknown() function.
<pre>        QAXAGG_IUNKNOWN;
</pre>The implementation of the <tt>IObjectSafety</tt> interface provides the caller
with information about supported and enabled safety options, and returns 
<tt>S_OK</tt> for all calls to indicate that the ActiveX control is safe.
<pre>        HRESULT WINAPI GetInterfaceSafetyOptions( REFIID riid, DWORD *pdwSupportedOptions, DWORD *pdwEnabledOptions )
        {
            *pdwSupportedOptions = INTERFACESAFE_FOR_UNTRUSTED_DATA | INTERFACESAFE_FOR_UNTRUSTED_CALLER;
            *pdwEnabledOptions = INTERFACESAFE_FOR_UNTRUSTED_DATA | INTERFACESAFE_FOR_UNTRUSTED_CALLER;
            return S_OK;
        }
        HRESULT WINAPI SetInterfaceSafetyOptions( REFIID riid, DWORD pdwSupportedOptions, DWORD pdwEnabledOptions )
        {
            return S_OK;
        }
    };
</pre>The implementation of the <tt>createAggregate()</tt> function just returns a new
<tt>ObjectSafetyImpl</tt> object.
<pre>    QAxAggregated *GLBox::createAggregate()
    {
        return new ObjectSafetyImpl();
    }
</pre>
<p> To build the example you must first build the <a href="qaxserver.html">QAxServer</a> library. Then run qmake and your make tool in 
<tt>examples/wrapper</tt>.
<p> <hr>
<p> The <a href="qaxserver-demo-opengl.html">demonstration</a> requires your
WebBrowser to support ActiveX controls, and scripting to be enabled.
<p> In contrast to the other QAxServer examples Internet Explorer will not
open a dialog box to ask the user whether or not the scripting of the GLBox
control should be allowed (the exact browser behaviour depends on the security 
settings in the Internet Options dialog).
<p> 

<pre>    &lt;SCRIPT LANGUAGE=JavaScript&gt;
    function setRot( form )
    {
        GLBox.setXRotation( form.XEdit.value );
        GLBox.setYRotation( form.YEdit.value );
        GLBox.setZRotation( form.ZEdit.value );
    }
    &lt;/SCRIPT&gt;

    &lt;p&gt;
    An OpenGL scene:&lt;br&gt;
    &lt;object ID="GLBox" CLASSID="CLSID:5fd9c22e-ed45-43fa-ba13-1530bb6b03e0"
    CODEBASE=http://www.trolltech.com/demos/openglax.cab&gt;
    [Object not available! Did you forget to build and register the server?]
    &lt;/object&gt;&lt;br&gt;

    &lt;form&gt;
    Rotate the scene:&lt;br&gt;
    X:&lt;input type="edit" ID="XEdit" value="0"&gt;&lt;br&gt;
    Y:&lt;input type="edit" name="YEdit" value="0"&gt;&lt;br&gt;
    Z:&lt;input type="edit" name="ZEdit" value="0"&gt;&lt;br&gt;
    &lt;input type="button" value="Set" onClick="setRot(this.form)"&gt;
    &lt;/form&gt;
</pre><p>See also <a href="qaxserver-examples.html">The QAxServer Examples</a>.

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